Filter press



June 30, 1936. A. M. WILSON ET AL FILTER PRESS Filed Dec. 30, 1933 2 Sheets-Sheet l ,NMMWIIW #M4550 RSS ma N NN Q H June, 30, 1936. A. M. WILSON ET Al. 2,045,740

FILTER PRESS Filed DeG. 30, 1935 2 ShebS-Sheet 2 f Je iig J9* l 26s EV] H fia d l I; .f [E )x7/'7d 1 i JH F z d F; 24 n.: V' ZO my? mam Patented June 30, 1936 UNITED STATES PATENT, OFFICE mman mass Arthur M. Wilson, Cranford, and vOgden E.'

Crosby, Linden, N. J., assignors to Standard Oil Development Company, a. corporation of Dela- This invention relates to an improvement in filter presses and will be understood from the following description when reading in conjunction with the drawings:

Flg. 1 of which is a longitudinal section through a rotary lter press; leallf'lg. .2 is an enlarged section through a filter Fig. 3 is a front view of a filter leaf;

Fig. 4 is a similar view of a lter leaf consisting of several segments; and

Fig. 5 is a section taken at II-II of Fig. 4.

In the art of filtration for the purpose of separating solids from liquids such as, for example, wax from petroleum oil admixed with a. solvent, it is customary to use either stationary'or rotary filter presses. In principle, such filter presses consist of a casing in which several filter leav are arranged covered with a filter blanket through which the liquid passes, but the solid is retained on its surface. The filter blanket may consist either of a cloth or of very fine wire screen. Liquid to be filtered is admitted to the casing and then forced by a pressure difference through the filter blanket and lter leaves from the interior of which it is removed while the solid accumulates on the exterior 4surface of the blankets. The iilter leaves with the blanket may be stationary or may be rotated. The pressure difference is either produced by positive pressure or by vacuum applied to the interior of the filter leaves.

We have discovered that the operation. of the iilter press is greatly improved by placing one or several coarse wire screens at central distances tion and 8 an inlet line for the solvent. 9 is the discharge line for the wax, I0 the discharge `line for washing solvent remaining in the press after washing and II is the discharge line for undewaxed solution. Lines I2 and I3 designate the discharge lines for solvent used in washing the wax cake and for the dewaxed solution respectively.

The solvent line I 4 runs the full length inside the press and has attached thereto spray tubes I I5. Refen'ing to Figs. 2 and 5, the filter leaf itself consists of two round perforated plates I6 which are held apart by the coarse wire screen I1. 'Ihe plates and. screen are fabricated into a rigid unit with the recessed rings I8 and' I9. The filter cloths 20 are clampedon either side of the leaf by means of clamping rings 2l The hub 22 is key seated to fit the hollow shaft. Appropriate ports are provided to allow the liquid to iiow from the inner part of the leaves into the hollow shaft. The coarse, wire screens of the present invention are shown at 23 and 24. They are attached by means of supports 25 to clamping rings 2|. Soldering provides the simplest attachment of supports 25 to the rings 2| andalso to the coarse wire screens. Other supports 26 are soldered to the coarse screen and are-rounded at their open end which faces the filter 'cloth to prevent piere- Y In the lter press illustrated in Figures 1 and 2,

the lter leaves are one unitand the clamping rings are the standard equipment so that the screens may be attached to these. In other presses, however, no clamping ring is present and in such cases the filter leaf may be provided with one or two rings to which the coarse wire screen of the present invention is attached. Furthermore, the filter leaf may consist of several segments, as shown in Figure 4. In this case two methods of attaching the coarse screens are possible.

(1)l One screen may be used for the entire leaf.

(2) An independent screen may be used for each segment. 'Ihe latter method is preferred because faulty leaf segments may be replaced without disturbing the remainder of` the leaf.

A suitable distance of the coarse wire screens of the present invention is about half an inch from each other and from the filter blanket. This distance may, however, be considerably varied.

The wire screen or screens placed in front of the filter blanket prevents the troublesome slipping of the solid material such as wax cakes which builds up on the blanket during the filtering operation. Although the use of such screens shows certain advantages with stationary filters, the greatest benefit is obtained from its use with rotary filters.

After a sufficiently thick layer of solid builds up on the filter blanket, the filtering operation is discontinued, the unfiltered liquid present in the filter 'case is removed, and the deposited solid is usually submitted to washing with a clean solvent. The wire screen of the' present invention will not only prevent the slipping or dislocation of the cake during the washing operation but more especially during the removal of the unltered liquid from the press.

'Ihis invention is not to be limited by the particular details given for the purpose of illustrating the invention but only by the following claims in which it is our intention to claim all novelty inherent in the invention.

What we claim is:

1. In combination with a rotary lter press a lter leaf, a lter blanket on said leaf and a ring for keeping the filter blanket in close contact with the filter leaf, and a coarse wire screen rigidly attached to said ring so as to be maintained at a suitable distance from and substantially parallel to the filter blanket whereby the iilter cake formed on theblanket is maintained in substantially xed relationship thereto.

2. In a lter press, a filter leaf carrying a illter blanket and a pair of clamping rings for the blanket, the improvement comprising a coarse wire screen rigidly supported on the rings, in spaced and parallel relationship thereto, by means of a plurality of supports aflixed to the screen and to the ringsv at suitable points thereon, whereby the filter cake formed on the blanket is substantially maintained in contact therewith durin'g filtering and washing operations.

3. In combination with a circular lter leaf,

carrying a lter blanket, clamping members for the filter leaf comprising a pair of. concentric ring members and a coarse wire screen rigidly secured to said ring members in spaced and parallel relationship thereto and to the lter blanket, said screen bearing a plurality of supporting members ailixed at various points upon the inwardly faced surface of the screen, extending into spaced relationship with the lter blanket and adapted to engage the blanket under pressure without piercing said blanket.

4. Apparatus according to claim 2 in which the clamping rings are formed of a plurality of frame members in the formrof truncate sectors of a circle, adapted to provide for radial engagement of the blanket with the filter leaf, each frame member carrying a coarse wire screen rigidly supported thereon, by means of a plurality of supports aixed to the screen and to the frame member at suitable points thereon whereby the filter cake formedon the blanket, exposed within the frame, is substantially maintained in contact therewith during ltering' and washing operations.

ARTHUR M. WILSON; OGDEN E. CROSBY. 

